Request for clarification from Ruiter et al regarding ‘Risk of cancer in patients on insulin glargine and other insulin analogues in comparison with those on human insulin: results from a large population-based follow-up study’. Reply to Carstensen B [letter]

Excerpt

To the Editor: We highly appreciate Dr Carstensen’s interest [1] in our study [2]. With regard to the first question, HRs are not reported per year but refer to the total period of exposure. We referred to an earlier paper from one of us in which an example on thiazide diuretics and hip fracture is described to explain how we usually analyse drug exposure as a time-dependent variable with categories for different durations of use [3]. On reading the first question by Dr Carstensen [1], we realise that the reference may have been confusing because in the current study we made a direct comparison between insulin glargine (A21Gly,B31Arg,B32Arg human insulin), other insulin analogues and human insulin in which, at the moment a tumour was diagnosed, the insulin exposure status (insulin glargine, human analogues or human insulin) in those diagnosed with cancer was compared with the exposure status of the remainder of the cohort members at the same day of follow-up since starting on insulin. In this way, our HR of 0.7 was an overall HR. …